With spiraling construction costs, it is of greater importance now than ever to provide techniques, articles, and methodology which will decrease the cost intrinsic with new construction. Heretofore, foam insulation primarily formed from rigid urethanes or the like have found its place in the construction art due to the intrinsic ability of the urethane foam's insulation and mechanical strength. Its uses have even migrated into other fields such as the automotive arts, in which the structural rigidity of the foam is enhanced by the provision of wire meshes, grids, and struts which are operatively interconnected so as to assume a portion of the load dissipation required by the panel. Additionally, coating of natural or synthetic materials of epoxy, fiberglass, or other materials disposed on the outer surfaces of the composite defined by the urethane foam core and the wire lattice enhance the structural capabilities of the panel while still providing lightweight construction techniques.
In the known prior art techniques for forming these panels that include wire or rod reinforcement, great difficulty has been perceived in the past in forming the requisite wire lattice and holding the same in place while the foam is poured into a mold in physical proximity to the lattice so that when the foam has been set, an integral unit has been provided.
While the inherent characteristics of utilizing foam has made it productive to apply the foam to the lattice after the lattice has been assembled, considerable difficulty has been experienced in maintaining the lattice in the appropriate orientation prior to and during the foam disposition process. Elaborate jigs and constraining devices are required to hold the lattice in its proper orientation, and these jigs and associated work holders interfere with the cavity defining the mold as can be readily understood.
The following citations are reflective of the state of the art and the associated problems therewith of which applicant is aware, to the extent that these citations appear to be germane to the process as hand:
U.S. Pat. Nos. 3,305,991 (Weismann); 4,104,842 (Rockstead et al.); 3,298,152 (Lockshaw); 4,125,981 (MacLeod et al.); 4,079,560 (Weismann); 4,241,555 (Dickens et al.); Article from Modern Plastics International, April 1979.
The patent to Weisman, U.S. Pat. No. 3,305,991 teaches the use of a method to produce modular structural panels. Liquid foam components are introduced into a prefabricated wire lattice as touched upon hereinabove. The foam such as polyurethane is disposed within a supporting wire grid or matrix, the foam thereafter being heated to provide an integral panel.
Likewise, Weismann U.S. Pat. No. 4,079,560 relates to a manufacturing of building panels consisting of a wire framework and a foam core similar to the process delineated immediately supra. As before, the latticework exists initially and must be supported prior to the disposition of the foam therewithin.
Likewise, Dickens et al. is of interest since they teach the use of a composite panel structure and method of manufacture in which the panel has an expanded plastic core with thin reinforcing strips bonded to front and back surfaces of the core at least along the edges thereof, and may have a wire grid attached in off set relation to one surface thereof for receiving a material such as concrete. Initially, the panel is manufactured by expanding a plastic material in a mold by the application of heat to form a core, removing the core from the mold, placing thin reinforcing strips on back and front surfaces of the core with an adhesive system between strips and the core, and returning the core to the mold and heating the interior of the mold to bond the strips to the core and achieve dimensional stability. It should be clear, that this citation refers only to panels having only wire grids and no wire lattice structure as will be made manifest in the ensuing discription of the preferred embodiment.
Likewise, Lockshaw relates to structural panel members with a high strength to weight ratio. These members are used to reinforce concrete and have no relationship to composite panels. Moreover, the method to produce them is dissimilar from the process at hand.
Rockstead et al. relates to a reinforced concrete building wall structure which enables the construction of walls having a completely open dead air space. See for example FIG. 5 reference numeral 43.
The "Modern Plastic International" article provides a basic background showing the environment within which the instant application and associated products is intended to be used. As pointed out therein, the building panels consisting of foam slabs are enclosed in a wire framework, which panels are assembled at the building site and thereafter finished with concrete or plaster. However, the methodology associated with forming the panels at the factory suffers from the maladies noted hereinabove.
The remaining citation shows the state of the art further.
By way of contrast, the instant invention is distinguished over the known prior art in that a foam core has been provided initially through which a plurality of rod like members are adapted to traverse. Subsequently, a grid defined by longitudinally and latitudinally extending bar members interconnected at the intersection are placed on opposed major surfaces of the foam core so that portions of the rods come in tangential registry with portions of the grid. Suitable affixion of the rods to the grid thereafter form a lattice without the difficulties associated with forming a lattice initially, holding same in a jig, and thereafter forming a foam core therewithin.